Formation of solvate structures by the ortho-, meta-, and para-isomers of hydroxybenzoic acid in supercritical fluid
- Authors: Antipova M.L.1, Gurina D.L.1, Odintsova E.G.1, Petrenko V.E.1
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Affiliations:
- Krestov Institute of Solution Chemistry
- Issue: Vol 91, No 4 (2017)
- Pages: 708-714
- Section: Structure of Matter and Quantum Chemistry
- URL: https://bakhtiniada.ru/0036-0244/article/view/169411
- DOI: https://doi.org/10.1134/S003602441704001X
- ID: 169411
Cite item
Abstract
The solvate structures formed by the ortho-, meta-, and para-isomers of hydroxybenzoic acid (o-HBA, m-HBA, and p-HBA) with a polar co-solvent (methanol at a concentration of 0.030 and 0.035 mole fractions) in supercritical carbon dioxide at a constant density of 0.7 g/cm3 and temperatures of 318 and 328 K have been studied by the classic molecular dynamics. It has been determined that a stable hydrogen-bonded complex with the co-solvent forms via the hydrogen of the carboxyl group for all isomers. The probability of this complex existence is high at all temperatures and concentrations. In the o-HBA molecule, the other functional groups are engaged in the intramolecular hydrogen bond, but not involved in interactions with methanol. It has been found that m-HBA and p-HBA can be involved in hydrogen bonds with methanol via hydroxyl hydrogen and oxygen atoms; they are characterized by the presence of one more co-solvent molecule (rarely, two molecules) in their solvation shell and intermittent formations/breakages of hydrogen bonds via other functional groups. These bonds are far less stable, and their formation is sensitive to change of temperature and co-solvent concentration. It has been concluded that the degree of selective solvation of m-HBA and p-HBA by co-solvent molecules is approximately the same, but the rate of structural rearrangements in the nearest environment of m-HBA is higher than that of p-HBA.
About the authors
M. L. Antipova
Krestov Institute of Solution Chemistry
Email: vep@isc-ras.ru
Russian Federation, Ivanovo
D. L. Gurina
Krestov Institute of Solution Chemistry
Email: vep@isc-ras.ru
Russian Federation, Ivanovo
E. G. Odintsova
Krestov Institute of Solution Chemistry
Email: vep@isc-ras.ru
Russian Federation, Ivanovo
V. E. Petrenko
Krestov Institute of Solution Chemistry
Author for correspondence.
Email: vep@isc-ras.ru
Russian Federation, Ivanovo
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